Wooohh !!! The box looks too low on the lock !!! It looks like it is below the bolster , the thick part on the back , inside of the lock , the bolt is to thread into .... Bottom of the square marking on the outside should be the bottom of the bolster on the inside. That center side plate screw needs to go right through the middle of that bolster .... Up and down wise . Then ....mark where the barrel ends ....thats the right side of the box , and then that set where the hammer rides , that engraved line ....that the left side of the box ....center punch the center.....